void FixedUpdate()
{
velocity = (rigidbody.transform.position - lastPosition) / Time.deltaTime;
localVelocity = rigidbody.transform.InverseTransformDirection (velocity);
localVelocity.y = 0;
speed = localVelocity.magnitude;
angle = HorizontalAngle (localVelocity);
lastPosition = rigidbody.transform.position;
}